Q10. The electronic configuration of the valence shell of Cu is 3d10 4s1 and not 3d9 4s2. How is this configuration explained?
Answer. This is explained by the orbital symmetry principle, which states that orbitals that are completely or partially filled in a given subshell have extra stability. As a result, the 3d10 4s1 copper configuration is more symmetrical and stable than the 3d9 4s2 configuration.
